nap through buckling occurs when a biological structures equilibrium state undergoes a shift, or rise / jump in energy states causing a snap or shift across a plane or line. This occurs when the structure suddenly displaces into another equilibrium configuration due to critical load being reached/satisfied. This is inversely proportional to the column height, and in the spinal column is called the critical state. This state occurs on the magnitude of 3x faster than any reflexive muscular contraction can fully react. In other words, the muscles provide zero protective mechanism to such an ‘assault’ on the biological tissues, resulting in trample damage to the involved tissues.
Multiple variables impact this phenomena. Direct impacts or compressive loading: loading rate (velocity & acceleration) of impact, angle of impact, posture of specific spinal structure (cervical, thoracic, lumbar), type of surface spine strikes, point of impact on skull. Inertial loading or acceleration/deceleration events: loading rate, posture of spinal structure (cervical, thoracic, lumbar), mass of objective (person involved at minimum), inertial effects of spine at specific segmental levels.
Complexity of snap through buckling is indicate by shapes of the spinal column. Lordosis is neutral shape, s-curve is an occurrence of a 1st order buckled mode, flex-extend-flex is a 2nd order buckled mode. 1st order have been produced under static and quasi-static compressive loads. 2nd order and higher require impact or dynamic loading, and are associated with large potential energies.
Buckling furthers to promote material degradation, and stress concentrations leading to a vicious cycle known as degenerative joint disease, osteoarthritis and inevitably degenerative disc disease. These are all further exacerbated and accelerated by poor structural spinal alignment prior to injury which predisposes a patient to an accelerated poor prognosis and outcome following long term follow up.
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